Acoustic device



NOV. 18, 1930. p MICHELL 1,781,988

ACOUSTIC DEVICE Filed April 26, 1929 2 Sheets-Sheet, 1

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ATTORNEY Nov. 18, 1930.

ACOUSTIC DEVICE Filed April 26, 1929 ZSheets-Sheet 2 IN V EN TOR.

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' ATTORNEY P. A. MIICHELL 1,781,988

which Patented Nov. 18, 1930 UNITED TA E PHILIP A. MICHEL-L, or miwnmonron; NEW YORK, nssrenon 'ro BRANDES LABO- BATORIES; INCL, NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY I Aoovs'r1c DEVICE is employedto transfervibrationsfrom'an armature member to a sound reproducing diaphragm with means for limiting the whipping action of the drive pin. 1

Another object ofiny invention is to proide means for'c'ontrolling'the movement of the drive pin ina magnetic type of sound reproducer for preventing rattling and'other noises 1n soundreproduction.

Still another object of my invention is to provide a construction of suspension member for the drive pin for avoiding'the setting up of rattling noises in the sound reproducer system. f y

A further object of my invention is to provide'a sheet metal member which may be'supported upon an electromagnetic dr vingsystom of a sound reproducer for suspending the drlve rod of the sound reproducer while limiting the whipping action thereof and preventing excessive vibration of'the sound reproducingdiaphragm to which the drive rod is connected.

Other and further objects of my invention reside in the construction of suspending memfiher for the drive pin of an electromagnetic sound reproducer as set forth'mor'e clearly reference to the accompanylng drawings, in

Figure 1 is a side elevation with parts partially broken away and parts shown in crosssection for illustrating the arrangement of the electromagnetic speaker system; ig. '2

is a plan view of the electromagnetic driving mechanism and suspension for the sound inproducing diaphragm set forth in Fig. 1; Fig. 3 is a front view of the drive pin mounting member ofiny invention; Fig. 4 is a cross-sectional view through the drive pin mounting member illustrated in Fig. 3 on line 44 thereof; Fig. 5 is a lateral c'ro'sssectio'nal view through the drive pin inount- Application filed April 26,

ph agms; the whipping actionfollowing by least sriai'uo. .2165,

ing member taken on line 5+5 of Fig. 3;

Fig. 6 is a side elevation of a modified form of drive pin mounting. embodying'the principles of my invention ;-Fig. of. the modifiedform of drive pin mounting 1llustrated in Fig. '6; Fig: 8 is a front View of the drivepin mounting shown in Figs. 6 and 7 Fig. 9

the "constructionof drive pin mounting illustrated-in 8 taken online 9 9 thereof;- and Fig:- l-Q is a lateral cross-sectional view through the drive pin mounting of Figs. and 90h line 10-1'Qof Fig. 8.

7 is a plan vlew is a cross-ser'ztional view of In electromagnetic sound reproducers e'ni ploying a conical shaped sound reproducing diaphragm, .I "have found Whipping action of the i sound reproducing diaphragm introduces rattles and other of music or sound which is being reproduced. In {conical shaped sou 'n which occurs as aresult of excessive movement pin which interconnects the vibrating armathat excessive noises in the jsound'reproducing system which Y tend to detract from the enjoyable qualitieswm I d reproduc ng; diaof the drive i ture niember with theapexof the cone tends to produce rattling of theldiaphr agm which 1 impairs the quality of the reproduced sound.

I have'found that highly desirable results are; obtained in sound reproduction where means are provided for suspending the drive pin which interconnects the moving armature with d'ucer in such manner that the armature memher is normally maintained centrally ofthe electromagnetic driving system; and excessive movement ofthe drive pin prevented by a balanced system'of forces which becomes effective when the drive pin tends to exceed apredetermined amplitude of movement re quired for the proper. reproduction of sound. The double lever arrangement of the suspension means which I employin mounting the drive pin asset forth in the drawings herein has been found to be" highly practical in its construction and successfulin its operation in eliminating whipping. fiction of the the conical 'shaped sound reprodrive pin wlth inherent noise disturbances.

...B; fii l' 9 th s f eii j 'j detail, r ence character 1. designatesa permanent mag- 38 1s reenforced by means-of ribs armature 20 have their not which may be of the horseshoe type havand 3. Reference character 4' and supported by means ofa plate 9 anjd a series of plate members 11 which area'djustable in position with respect to member 8 by adjusting screws 13- Electromagnetic wind ing 12 is wound upon bobbin 10. which is apertured at 18 to receive armature member 20 which .is centrally, pivoted within the winding. A drive pin 19exten ds from armature 20 and is supported at its outer extremity by means of the double lever-formedby strip 22.v The strip 22 is-secnred to one end of the member 7 and isbent upon itself as indie cated at 23 extending in a'plane parallel to the portion 22 as represented at24. The portion. of the strip 22is strengthenedby means of ribs 27 pressed in the face of the strip. The portion 2a is strengthened by means of ribs 25. An aperture 26is formed in the strip 22 to permit the passage of drive rod 19 therethrough, The end of drivesrod 19 is secured in the extremity of portion 24 of strip member 22 by means of solder or clamps, or insome other suitable manner. The conical shapedsound reproducingdiaphragm 28 ssecured to the drive pin 19 by means of clamping nuts 29 and 30 which grip opposite sides of theapex of the sound reproducing diaphragm. 5 1-. r

Instead ofproviding a return bend strip for suspending the drive pinl9, I may press the suspension strip rom a flat sheet of n'iaterial which I have represented in Figs. 6 to 10 where the strip 38 is apertured at 32 with a tongue 33 struck out therefrom and extending ina plane parallel totheplane of strip 38,'but offset therefronn The strip adjacent the edgesthereof. The is reenforced by means of ribs 34 formed adi jacent the edges thereof. j The drive pin 19 is anchored in the extremity of the tongue 33. 2

Referring to Figs. 4c and 9, the forces which are set up wider the action. of the vibrating direction indicatedbjv arrows 39 and 40. That is, the portions of the suspension member 22 or 38 are free to move relative to each other in a rolling or rocking action which is free of Whipping action'by virtue of the normal. resiliency of the parts of the suspension device. Any tendency of the portion 24 to move toward the plate 22, or the tongue- 83 to move toward the plate 38is resisted by a restoring force tongue 33 and 17, which provide the portion8- of member-'7 I mit the passage 31 formed ments of my invention, I desire-that it be -unde'rs'tood that modifications "may be made and that no limitations upon my invention are'intended other than are imposed by the scope oftheappended claims.

hat I claim as new and desire to secure by Letters Patent of the United Statesis as follows: v v p 1. In an electromagnetic sound reproducer, a vibratory armaturemember, a sound reproducing diaphragm, a drive pin interconnecting jsaid armature member with, said soundreproc'lucing diaphragm, and means for suspending said drivepin comprising a resilient strip of material bent upon itself,

'Said drive pin passing through one portion of said resilient strip and being connected to another portion thereof; 7

2. In an electromagnetic sound reproducer, a, vibratory armaturemember, a sound reproducing diaphragm, a drive pininterconnecting said armature member with said sound reproducing .diaphragnn'and suspension means for said drive pin, said suspension means comprisinga strip of material having a pair of parallel extending portions with one of said parallel extending portions secured tosaid drive pin, and the other of said parallel extending portions apertured to perofsaid drive pin therethrough for connection to the first mentioned portion of said strip.

3. In an electromagnetic sound reproducer, a :vibra-tory armature member, a sound reproducing diaphragm, a drive pininterconnecting said armature member with said soundreproducing diaphragm, and suspension 'ineans forsaid drive pin comprising a resilient strip of material permanently ported at one endand J connected at the other end witlr a' portion:of said (lI'lVG }.)ll1,f$ti(l strip being bent'npon itself and apertured in. one portion thereof to'pern'lit the passagef of said drive pin therethiough for connection to the end of said strip 4. In an electromagnetic sound reproducer, a vibratory armature member, a sound reproducing diaphragn1,.a drive pin interconnecting said armature' memberwvith said sound reproducing diaphragm, and suspening apertured forthe passage of said drive pin therethrough, the portions of said strip being relatively movable for controlling the movement of said drive pin. 7

5. In an electromagnetic sound reproduoer, a vibratory armature member, a sound reproducing diaphragm, a drive pin interconnec-tlng said armature member With said sound reproducing diaphragm, and suspenanother portion thereof for the passage of said drive pin therethrough for connection to the first mentioned portlon of sald resilient strip whereby excessive movement of said drive pin is eliminated.

PHILIP A. MICHELL. 

